Water heater with counter-twisted baffle

ABSTRACT

A water heater including a storage tank, a combustion chamber, a burner for producing products of combustion, the burner positioned in the combustion chamber, a flue extending from the combustion chamber through the storage tank, and a baffle positioned within the flue and directing the flow of the products of combustion through the flue. The baffle includes multiple clockwise twist segments and multiple counterclockwise twist segments.

BACKGROUND OF THE INVENTION

The present invention relates to water heaters, and more particularly towater heaters including flue baffles.

A flue baffle is positioned in the flue tube of a gas-fired waterheater. A burner combusts a fuel and air mixture to create products ofcombustion or exhaust gases. The gases flow through the flue tube toheat the water stored in a tank. The baffle enhances the heat exchangerate between the gases and the water stored in the tank.

SUMMARY OF THE INVENTION

The present invention provides, in one aspect, a water heater includinga storage tank, a combustion chamber, a burner for producing products ofcombustion, the burner positioned in the combustion chamber, a flueextending from the combustion chamber through the storage tank, and abaffle positioned within the flue and directing the flow of the productsof combustion through the flue. The baffle includes multiple clockwisetwist segments and multiple counterclockwise twist segments.

The present invention provides, in another aspect, a baffle for use inthe flue of a water heater to direct the flow of products of combustionthrough the flue. The baffle includes multiple clockwise twist segmentsand multiple counterclockwise twist segments.

Other features and aspects of the invention will become apparent byconsideration of the following detailed description and accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a water heater.

FIG. 2 is a perspective view of a baffle of the water heater of FIG. 1.

FIG. 3 is a front view of the baffle of FIG. 2.

FIG. 4 is a side view of a portion of a sheet used to form the baffle ofFIG. 1.

FIG. 5 is a front view of a second embodiment of a baffle.

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways. Also, it is to be understood thatthe phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting.

DETAILED DESCRIPTION

FIG. 1 illustrates a water heater 100 including a base pan 105, a tank110 supported by the base pan 105 and containing water, an insulatingjacket 115 surrounding the tank 110, and a burner 120. A flammable fuelis provided to the burner 120 by a fuel inlet 125 connected to a fuelvalve 130. The burner 120 is positioned in a combustion chamber 135beneath the tank 110. The fuel valve 130 is connected to a fuel supply.The fuel can be, for example, natural gas or propane. The combustionchamber 135 is connected to an air supply, for example, the atmospherearound the water heater 100. A flue tube 140 extends from the combustionchamber 135 through the tank 110. The flue tube 140 includes a centrallongitudinal axis 145. The products of combustion or exhaust gasescreated by the burner 120 flow through the flue tube 140 to heat thewater stored in the tank 110. A cold water inlet pipe 150 supplies coldwater to the tank 110. A hot water supply pipe 155 supplies hot water toan end-use location, for example, a faucet. The water heater 100 asdescribed above is conventional.

As shown in FIG. 1, a baffle 160 is positioned within the flue tube 140.A hanger or cross-bar 165 supports and positions the baffle 160 withinthe flue tube 140. In some embodiments, other suitable means are used tosupport and position the baffle 160 within the flue tube 140. The baffle160 extends longitudinally within the flue tube 140. Preferably, acentral longitudinal axis 170 of the baffle 160 is collinear with thelongitudinal axis 145 of the flue tube 140. The baffle 160 is positionedwithin the flue tube 140 to leave a space 172 between the lower end ofthe baffle 160 and the lower end of the flue tube 140. The space 172facilitates mounting the flue tube 140 and baffle 160 on a glass coatingmachine that coats the inside and outside of the flue tube 140 and thebaffle 160 with a protective coating to resist degradation or corrosionof the flue tube 140 and baffle 160. Also, the space 172 makes thebaffle 160 less likely to be overheated by extreme temperatures in thecombustion chamber 135. The space 172 can be, for example, about threeinches (7.62 centimeters) in length but such length may vary based onmanufacturing parameters. In other embodiments, the lower end of thebaffle 160 is flush with the lower end of the flue tube 140.

As shown in FIGS. 2-3, the baffle 160 includes six clockwise twistsegments or twists 175 and six counterclockwise twist segments or twists180 that alternate with each other along the longitudinal axis 170 ofthe baffle 160 so that each clockwise twist 175 is adjacent to acounterclockwise twist 180. A substantially flat or planar spacer 190 ispositioned between each adjacent clockwise twist 175 andcounterclockwise twist 180. Each spacer 190 is positioned in a verticalplane that includes the longitudinal axis 170. The length of each spacer190 along the longitudinal axis 170 can vary as necessary. Preferably,the length of a spacer is 0.36 inches (0.91 centimeters). Preferably,each clockwise twist 175 is a one hundred eighty degree twist and eachcounterclockwise twist 180 is a one hundred eighty degree twist. Thatis, a sheet or plate 195 is twisted clockwise one hundred eighty degreesabout the longitudinal axis 170 to form a clockwise twist 175 and thenthe same sheet is twisted counterclockwise one hundred eighty degreesabout the longitudinal axis 170 to form a counterclockwise twist 180.The length of each clockwise twist 175 along the longitudinal axis 170is substantially the same and the length of each counterclockwise twist180 along the longitudinal axis 170 is substantially the same. In someembodiments, each clockwise twist 175 is twisted more or less than onehundred eighty degrees and each counterclockwise twist 180 is twistedmore or less than one hundred eighty degrees. For example, each twist175 and 180 could be twisted ninety degrees or three hundred sixtydegrees. More or fewer twists 175 and 180 can be included as necessary.Preferably, the baffle has a diameter of 3.625 inches (9.207centimeters) and an overall length of 45.25 inches (114.9 centimeters),the length along the longitudinal axis 170 of each of the twists 175 and180 is between three inches (7.62 centimeters) and six inches (15.24centimeters), and the flue tube 140 has a diameter of four inches (10.16centimeters). In some embodiments, a spacer 190 is not positionedbetween each adjacent clockwise twist 175 and counterclockwise twist180. In other embodiments, the spacer 190 is corrugated.

As shown in FIGS. 1-3, the baffle 160 is corrugated. FIG. 4 shows a sideview of a portion of the sheet 195 used to form the baffle 160 beforethe sheet 195 is twisted. The sheet 195 includes an alternating seriesof peaks 200 and valleys 205 that form the corrugations. Alternatively,the baffle 160 is manufactured from a substantially flat or planar sheetor plate. The sheet 195 can be manufactured of mild (i.e., low carbon)steel, stainless steel, Inconel®, nickel alloy, or other suitablematerials. For example, the baffle 160 can be cold formed from a steelsheet 195. However, cold forming a steel sheet 195 limits how short of atwist length can be formed for each of the twists 175 and 180. It is tobe understood that other processes and/or methods of processing amaterial to form the baffle 160 fall within the scope of the invention.For example, the clockwise twists 175 and the counterclockwise twists180 can be formed individually and then secured together, for example,by welding, brazing, or soldering.

FIG. 5 shows an alternative baffle 360 similar to the baffle 160.Components similar to those of the baffle 160 described above arenumbered in a similar fashion plus two hundred. The baffle 360 has avarying pitch so that the length of at least one of the clockwise twists375 along the longitudinal axis 370 varies with respect to the length ofa different one of the clockwise twists 375 and so that the length of atleast one of the counterclockwise twists 380 along the longitudinal axis370 varies with respect to the length of a different one of thecounterclockwise twists 380. The baffle 360 includes three groups 210,215, and 220 of twists 375 and 380. In the first group 210, the lengthsof each of the clockwise twists 375 and the counterclockwise twists 380are a first length. In the second group 215, the lengths of each of theclockwise twists 375 and the counterclockwise twists 380 are a secondlength different than the first length. In the third group 220, thelengths of each of the clockwise twists 375 and the counterclockwisetwists 380 are a third length different than both the second length andthe first length. Preferably, the first length is three inches (7.62centimeters), the second length is four inches (10.16 centimeters), andthe third length is five inches (12.7 centimeters). More or fewer groupsof twists 375 and 380 of the same length can be used as necessary. Thenumber of twists 375 and 380 in a group can vary and a group can consistof a single twist 375 or 380.

In use, the burner 120 combusts a fuel and air mixture to createproducts of combustion or exhaust gases. The gases exit the combustionchamber 135 and enter the lower end of the flue tube 140. As the gasesencounter the baffle 160, the gases are directed in a circuitous pathalong the alternating clockwise twists 175 and counterclockwise twists180. The alternating clockwise twists 175 and counterclockwise twists180 create tangential and radial movement of the gases which increasesboth the amount of contact between the gases and the wall of the fluetube 140 and the turbulent kinetic energy of the gases. These in turnincrease the heat transfer rate between the gases and the water storedin the tank 110. Additionally, the twists 175 and 180 increase theresidence time of the gases within the flue tube 140, which alsoincreases the heat transfer rate. The corrugations of the baffle 160improve the radiative heat transfer when compared to a non-corrugatedbaffle. Also, the corrugations increase the amount of turbulent flow inthe gases, which increases the convective heat transfer when compared toa non-corrugated baffle. Enhancing the heat transfer rate between thegases and the water stored in the tank 110 improves the energy factor(EF) of the water heater 100. The baffle 160 with alternating clockwisetwists 175 and counterclockwise twists 180 significantly increases theheat transfer rate as compared to a baffle with twists all in the samedirection. Shorter twist lengths, which result in more twists 175 and180 for a baffle 160 of a certain length, provide the most heat transferenhancement. However, the pressure drop caused by the baffle 160 alongthe flue tube 140 increases as the twists lengths decrease. The baffle360 with twists 375 and 380 of varying lengths helps to optimize theheat transfer rate in relation to the pressure drop. Also, the length ofthe spacers 190, 390 can be varied to assist in optimizing the heattransfer rate in relation to the pressure drop. Various features of theinvention are set forth in the following claims.

1. A water heater, comprising: a storage tank; a combustion chamber; aburner for producing products of combustion, the burner positioned inthe combustion chamber; a flue extending from the combustion chamberthrough the storage tank; and a baffle positioned within the flue anddirecting the flow of the products of combustion through the flue, thebaffle including a plurality of clockwise twist segments and a pluralityof counterclockwise twist segments.
 2. The water heater of claim 1wherein the baffle further includes a longitudinal axis and wherein theclockwise twist segments alternate with the counterclockwise twistsegments along the longitudinal axis.
 3. The water heater of claim 1wherein each of the clockwise twist segments twists one hundred eightydegrees and wherein each of the counterclockwise twist segments twistsone hundred eighty degrees.
 4. The water heater of claim 1 wherein thebaffle is corrugated.
 5. The water heater of claim 1 wherein the bafflefurther includes a longitudinal axis and wherein the length along thelongitudinal axis of at least one of the clockwise twist segments varieswith respect to the other clockwise twist segments and wherein thelength along the longitudinal axis of at least one of thecounterclockwise twist segments varies with respect to the othercounterclockwise twist segments.
 6. The water heater of claim 2 whereineach of the clockwise twist segments twists one hundred eighty degreesand wherein each of the counterclockwise twist segments twists onehundred eighty degrees.
 7. The water heater of claim 6 wherein thebaffle is corrugated.
 8. The water heater of claim 7 wherein the lengthalong the longitudinal axis of at least one of the clockwise twistsegments varies with respect to the other clockwise twist segments andwherein the length along the longitudinal axis of at least one of thecounterclockwise twist segments varies with respect to the othercounterclockwise twist segments.
 9. The water heater of claim 6 whereinthe length along the longitudinal axis of at least one of the clockwisetwist segments varies with respect to the other clockwise twist segmentsand wherein the length along the longitudinal axis of at least one ofthe counterclockwise twist segments varies with respect to the othercounterclockwise twist segments.
 10. The water of claim 9 wherein aspacer is positioned between an adjacent clockwise twist segment andcounterclockwise twist segment, wherein the clockwise twist segments arecorrugated, and wherein the counterclockwise twist segments arecorrugated.
 11. The water heater of claim 2 wherein the baffle iscorrugated.
 12. The water heater of claim 2 wherein the length along thelongitudinal axis of at least one of the clockwise twist segments varieswith respect to the other clockwise twist segments and wherein thelength along the longitudinal axis of at least one of thecounterclockwise twist segments varies with respect to the othercounterclockwise twist segments.
 13. The water heater of claim 2 whereina spacer is positioned between an adjacent clockwise twist segment andcounterclockwise twist segment.
 14. The water heater of claim 13 whereinthe clockwise twist segments are corrugated and wherein thecounterclockwise twist segments are corrugated.
 15. A baffle for use inthe flue of a water heater to direct the flow of products of combustionthrough the flue, the baffle comprising: a plurality of clockwise twistsegments; and a plurality of counterclockwise twist segments.
 16. Thebaffle of claim 15, the baffle further comprising a longitudinal axisand wherein the clockwise twist segments alternate with thecounterclockwise twist segments along the longitudinal axis.
 17. Thebaffle of claim 16 wherein each of the clockwise twist segments twistsone hundred eighty degrees and wherein each of the counterclockwisetwist segments twists one hundred eighty degrees.
 18. The baffle ofclaim 15 wherein each of the clockwise twist segments twists one hundredeighty degrees and wherein each of the counterclockwise twist segmentstwists one hundred eighty degrees.
 19. The baffle of claim 15 whereinthe baffle is corrugated.
 20. The baffle of claim 15 the baffle furthercomprising a longitudinal axis and wherein the length along thelongitudinal axis of at least one of the clockwise twist segments varieswith respect to the other clockwise twist segments and wherein thelength along the longitudinal axis of at least one of thecounterclockwise twist segments varies with respect to the othercounterclockwise twist segments.